1. Field of the Invention
The present invention relates to a headset communication unit, and more particularly to rotating structures of the headset communication unit.
2. The Related Art
U.S. Pub. No. 2004/0052364 disclosed a headset communication unit. The headset communication unit comprises a housing, an ear hook mounted on the housing and a microphone arm pivotally connected to the housing. The housing has a pair of opposite first pivotal portions disposed thereon.
The microphone arm pivotally connected to the housing rotates between an opening status and a closing status. The microphone arm comprises an upper housing and a lower housing combined with the upper housing. A microphone and a torsion spring are contained between the upper housing and the lower housing. The lower housing has a connecting end and a tail end and has a pair of opposite second pivotal portions respectively extending upwardly from the two sides of the connecting end. The second pivotal portion has a pivotal hole defined therethrough. A pair of latch cavities are formed at the top and the bottom ends of the wall of the second pivotal hole. The second pivotal hole pivotally connects with one end of a pivotal axle. A pair of latch portions extend from the top and bottom ends of the end of the pivotal axle. The latch portion is held in the respective latch cavity to prevent the pivotal axle from rotating relative to the second pivotal portion. The other end of the pivotal axle pivotally connects with the corresponding first pivotal portion of the housing. The pivotal axle further has a penetrating hole defined in the axle center therethrough.
The torsion spring is approximate V-shaped and comprises a pair of elastic arms respectively bending and extending into the corresponding penetrating hole of the pivotal axle. In the process of the microphone arm rotating from the opening status to the closing status, the pivotal axle moves outwardly or inwardly.
However, the structures that enable the microphone arm to rotate around the housing in the above headset communication unit need the corresponding latch structures between the second pivotal portion and the pivotal axle to prevent the pivotal axle from rotating relative to the second pivotal portion. In the process of the pivotal axle rotating following the second pivotal portion and the pivotal axle moving outwardly and inwardly, an interaction force is produced between the latch cavity and the latch portion. As time passes, some bad conditions such as looseness will be produced between the latch structures. As a result, the microphone arm will can not rotate around the housing reliably. Besides, the above structures mentioned are comparatively complex.